Spoil mother and boy with English preserve (9)
I believe the answer is:
marmalade
'preserve' is the definition.
(I know that marmalade is a type of preserve)
'spoil mother and boy with english' is the wordplay.
'spoil' becomes 'mar' (synonyms).
'mother' becomes 'ma' (ma can mean mother).
'and' is a charade indicator (letters next to each other).
'boy' becomes 'lad' (informal term for boy).
'with english' becomes 'e' (abbreviation. I am not sure about the 'with' bit.).
'mar'+'ma'+'lad'+'e'='MARMALADE'
Can you help me to learn more?
(Other definitions for marmalade that I've seen before include "Spread" , "Preserve made with citrus fruits" , "Eleven's [PRESERVE]" , "group?" , "confiture" .)